Step into the Twilight Zone: Can Earthlings Adjust to a Longer Day on Mars?

"Mutinous" is not a word frequently used to describe teams of NASA scientists and engineers.

But that's precisely the term employed by Harvard University sleep scientist Charles Czeisler to explain what happened when the group operating the Pathfinder mission's rover in 1997 was required to live indefinitely on Mars time.

"They didn't really have a plan for dealing with the Martian day before they went up, and the rover lasted a lot longer than it was supposed to, so they actually had a mutiny and wanted to shut the thing off because they were so exhausted," he says, drily adding the obvious: "NASA wasn't too happy with that notion."

The Mars day, called a sol, is 39 minutes and 35 seconds longer than an Earth day. Every time NASA lands a robot on the Red Planet, its operations team must adapt to that long Martian day for the first period of roving, to take full advantage of the hours between the data transmission at the end of the rover's day and the upload of new commands the following Mars morning.

Staying up for 40 minutes extra each day, as Harvard sleep scientist Laura Barger points out, doesn't sound like much. "When you first think about it, it even sounds like a good thing, having a little extra time," she says. But not for long: The team's work schedule floats through two time zones every three days, while its actual location merrily persists in its normal light-dark habits. The team creeps from day shifts to night shifts and back.

Living for long on this perpetual Mars lag has proved extraordinarily unpopular. Joy Crisp, now a principal scientist at the NASA Jet Propulsion Laboratory, recalls the Pathfinder mission, which initially was expected to last seven days but ultimately endured 85. Nobody had planned for it. "I just remember getting to day 30 and thinking, 'I can't keep this up,'" Crisp says. Neither could anyone else, and the disgruntled staff forced NASA leadership to drastically change the schedule.

The agency was more prepared for the Spirit and Opportunity rover missions in 2004 and asked Czeisler to chair an advisory panel about how to handle the Mars time adjustment. But such guidance lost its utility when the two rovers landed within three weeks of each other on opposite ends of Mars—the equivalent of Denver and New Delhi—resulting in hordes of enthusiastic but exhausted workers bouncing between three time zones on two planets.

NASA leaders claim they have become more sensitive to the issue over the years. Andrew Mishkin, who helped plan the Curiosity mission, says that for the first time NASA officials decided to put a definitive three-month cap on Mars time. They also scheduled people to work no more than four days in a row, encouraged employees to monitor their own and their colleagues' fatigue levels, and had Human Resources prowl the lab for zombied workers to send home. "But everybody was pretty tired of it by November," when the 90th sol finally set, Mishkin says. And when NASA officials wanted to extend the Mars schedule past the 90th sol because the rover was running behind schedule, they put it up to a democratic vote: The answer was a resounding "No."

Research indicates there is more NASA could do for these tired people. Barger led an experiment using volunteers from the Phoenix lander operations crew in 2008, providing them with education about circadian rhythms, specific sleep-wake and caffeine schedules to adhere to, and countermeasures such as blue-light boxes to place on their desks. The 19 volunteers were monitored with medical tests, and their progress was tracked with wristwatch-size detectors. The experiment was limited by a small sample size and no control group, but 87 percent of participants reported they were able to adjust to the sol.

One might imagine that NASA would have leapt on research like this and provided the same countermeasures for its Curiosity mission, but it did not. Harvard sleep scientist Steven Lockley says NASA simply doesn't take human factors as seriously as it should, adopting our culture's flippant "I'll sleep when I'm dead" attitude about getting rest. To make matters worse, NASA's ranks are filled, he says, with "highly motivated A types who think they can overcome anything—but that's not true, because biology is there for everyone."

Such glibness can have consequences far worse than a group of grumpy, exhausted engineers, sleep scientists say. "It's a little shortsighted because you can spend hundreds of millions of dollars on a mission but not pay attention to human factors, and that's one of the things that can easily go really, really wrong," Lockley says.

The problem will most likely get more attention if NASA eventually sends a manned mission to Mars. The astronauts on such a mission would probably adapt to the sol with relative ease because they would be receiving all the appropriate light-dark signals, sleep scientists predict. But if it was a prolonged mission that lasted months or years, NASA would have to become more proactive about helping people entrain to a Mars schedule or else come up with an alternative staffing plan for its support crew back on Earth.

Otherwise, it could face another mutiny.

Check in later this week for my posts to the Expeditions Blog on my own experiment to see how it feels to live on Mars time.